In the Catholic Church, the liturgical book containing the Divine Office assigned to the Canonical Hours, the daily recitation of which is binding upon all in major orders and upon certain religious. Besides the Roman Breviary, the use of which is immeasurably the most widespread, there also exist monastic breviaries, e.g., Benedictine and Dominican, and books corresponding to the Breviary for those using rites other than the Roman, e.g., the Horologion of the Byzantine Rite. The Anglican form of the Breviary is based to some extent upon the Sarum Breviary, a variant of the early Roman Breviary, with later modifications.

The Roman Breviary is usually issued in four volumes corresponding to the four seasons of the year. Prior to the 11th century the various forms of prayer that constitute the Office were contained in separate books, Psalter, Antiphonary, Responsoral, Lectionary, Homiliary, Passionary, Collectorium, etc. To facilitate the private recitation of the Office, these books were compiled into a single volume, without musical notation, and abbreviated in other ways; the abridgment was known as a Breviary. This convenient volume, first used by the papalchapel, was adopted with modifications in the 13th century by the Franciscans, under whose influence its use became widely diffused. In 1568PopePius V issued a new edition, the use of which was made obligatory upon all of the Roman Rite with the exception of some who might continue to use certain old local and monastic breviaries.

Since the 16th century the Roman Breviary has undergone several revisions in the interest of critical scholarship and in accordance with the traditional spirit of the Liturgy: e.g., the introduction of the revised Vulgate text in 1598; the simplification of the rubrics in 1602; the correction of the hymns in 1632. PopeSaintPius X in the revision of 1911, shortened the Dominical and ferial offices, changed many rubrics regarding the rank of feasts, and redistributed the psalms to bring about the weekly recitation of the Psalter. From time to time new feasts are added. see also: Divine Office